1. Field of the Invention
The present invention relates to a process for carbonylating olefinically unsaturated nitriles, e.g., 3-pentenenitrile and acids, e.g., 3-pentenoic acid using certain sulfone solvents, e.g., tetramethylene sulfone to produce highly linear products.
2. Description of the Prior Art
According to U.S. Pat. No. 4,224,237 issued on Sept. 23, 1980, losses of rhodium catalyst are significantly reduced when the reaction of hydrogen and oxides of carbon are conducted within the presence of an organic sulfone solvent. European patent application No. 0,048,046 published on Mar. 24, 1982 teaches that ethylidene diacetate can be produced with good selectivity by reacting methyl acetate and/or dimethyl ether with carbon monoxide and hydrogen in the presence of a catalyst comprising a group VIII metal compound and a bromine- or chlorine-containing compound as a promoter. The reaction is conducted in the substantial absence of water but in the presence of a sulfur-containing polar solvents, e.g., sulfones, sulfoxides and cyclic sulfones.
Carboxylation of organic substrates such as acetophenone and acetone using alkaline phenolates as catalysts is taught in U.S. Pat. No. 4,032,555 issued on June 28, 1977 to be enhanced by the employment of certain oxygenated solvents such as cyclic ethers, e.g., tetrahydrofurane, aliphatic tertiary amines, e.g., triethylamine, heterocyclic tertiary amines, e.g., picoline and cyclic sulfones, e.g., sulpholane.
U.S. Pat. No. 3,505,394 issued on Apr. 17, 1970 discloses oxidative carbonylation in a reaction medium comprising numerous liquid organic solvents including sulfones. The use of a variety of solvents including sulfones in the reaction of butadiene with carbon dioxide in the presence of an amalgam of alkali or alkaline earth metals is disclosed in U.S. Pat. No. 3,686,299 issued Aug. 22, 1972. U.S. Pat. Nos. 4,238,357 issued on Dec. 9, 1980, 4,313,893 issued on Feb. 2, 1982 and 4,344,866 issued on Aug. 17, 1982 disclose a process having improved yields and selectivities of oxygenated organic compounds obtained by contacting an olefinically unsaturated compound with carbon monoxide and a compound containing a replaceable hydrogen atom over a catalyst comprising cobalt and/or ruthenium carbonyl and a promoter ligand consisting of heterocyclic nitrogen compounds and phosphorus or sulfur oxides. Sulfones are among the numerous ligands disclosed. It is believed that these promoter ligands do not function as solvents as evidenced by the fact that the use of solvents not including the sulfur-containing compounds is discussed elsewhere in the specification. Further support for this conclusion is that the rate of reaction is taught to substantially decrease as the ratio of ligand to cobalt and/or ruthenium carbonyl increases.
U.S. Pat. No. 3,346,625 issued on Oct. 10, 1967 discloses a process for the oxidative carbonylation of olefins using a platinum catalyst and, optionally, a redox reagent and an inorganic dehydrating agent such as a molecular sieve. The Patentees teach that the reaction can be conducted in a liquid phase organic solvent and include within their operable solvents ketone, amides, sulfones, ethers, esters, lower molecular weight fatty acids or benzene carboxylic acids. No particular advantage is assigned to the use of sulfone solvents.